Rich Communication Services (RCS) is defined by the GSM Association (GSMA) to specify services based on the IP Multimedia Subsystem (IMS), as specified by the 3rd Generation Partnership Program (3GPP). When an electronic device supporting an RCS technology sends a multimedia-message, it generally uses a manner of instant messaging if the network is available, and uses a manner of short message or a multimedia message if the network is unavailable. However, the fee for sending a multimedia message is relatively high. When the network is not online, the transmission of the multimedia-message may result in waste of costs. Therefore, further improvement is needed.